As an introduction to the problems solved by the present invention, consider the conventional flat panel matrix display having a row-column array of picture elements (pixels), each pixel at the intersection of a row and a column. Display in such pixels is conventionally accomplished by a display cell matrix aligned with the pixel matrix so that each display cell is addressed as a member of one row and one column. In an active matrix display, where each display cell includes at least one switch, each display cell is addressed for enabling display when it receives a column pointer signal and a row pointer signal. Many thousands of such pointer signals are needed to address a moderate size matrix of, for example, one million pixels arranged in one thousand rows and one thousand columns. Without integrated circuit packaging techniques, reliable displays having so many interconnections are not economically feasible.
One type of matrix display includes the field emission display wherein the matrix of display cells, circuits for generating the column and row pointer signals, and all the interconnecting conductors are formed on an integrated circuit substrate. Although it would be highly desirable to form video signal processing circuits on the same substrate, further integration of such support circuitry on the substrate has been frustrated by the excessive amount of substrate surface area occupied by conventional addressing circuits, and the excessive power consumed by such circuits.
Conventional video signals are sophisticated, requiring considerable circuitry for deriving color and intensity information for each pixel. In the conventional video signal, row and column addressing information must be derived from the video signal by synchronizing higher frequency clock signals with the video signal, by counting pulses, by detecting pulse frequency, and by detecting pulse duty cycle. Using conventional circuitry, these functions cannot be economically formed on the integrated circuit substrate with other display circuitry because conventional circuitry requires considerable substrate surface area, consumes excessive power, and is so complex that overall reliability goals cannot be economically met.
Without economical integrated circuit displays, systems designs will be limited to use of bulky, unreliable cathode ray tube displays, slow, dim liquid crystal displays, and expensive electroluminescent displays. Such limitations on systems designs will effectively prohibit introduction of new, portable, long life, reliable, and sophisticated industrial and consumer products in wide ranging fields including, for example, such fields as instrumentation, communications, entertainment, photography, and information processing.
In view of the problems described above and related problems that consequently become apparent to those skilled in the applicable arts, the need remains in matrix display products for improved matrix displays and methods for synchronizing such displays with an input signal.